A conventional radial electric spring clutch, also referred to as a solenoid actuated device, provides a well known means in the art for enabling high torque capacity with low activation energy. FIG. 1 is a cut away perspective view of a conventional electric spring clutch 10 and is shown to clearly identify the workings of the same for background purposes with respect to the present invention. In a typical spring clutch, electric current is passed through a stationary coil 15. Responsive to the current, lines of magnetic flux 20 are generated and used to attract a floating control ring 25 to a shoulder 30. Shoulder 30 is connected to hub 40 and output shaft 45. Control ring 25 is attached to one end of wrap spring 35. The other end of wrap spring 35 is attached to neck 47 of input gear 50. As input gear 50 is turned, wrap spring 35 wraps down onto neck 47 and hub 40. Thus, torque is transferred from the input 50 (and neck 47) through the wrap spring 35 to hub 40 and output shaft 45 when control ring 25 is attracted to shoulder 30.
Importantly, the lines of magnetic flux 20 pass through casing (or housing) 55 about stationary coil 15. Although casing 55 may comprise one or more components pressed or attached together, casing 55 (and/or all its components jointly) is stationary relative to the rotation of input gear 50 and output shaft 45. Magnetic flux 20 is forced to skirt outside of casing 55 and pass through control ring 25, thus forcing it against shoulder 30, because component 60 does not conduct the magnetic flux. The attraction of the control ring 25 to shoulder 30 upon energizing of coil 15 produces the solenoid (or clutch) effect to engage output shaft 45 with the rotation of input gear 50. Conversely, after electric current is removed from coil 15, the magnetic attraction is lost, thus causing the solenoid or clutch to disengage as the wrap spring 35 unwraps from hub 40 and neck 47.
Conventional solenoid (or electric clutch) devices have many uses and provide an effective means for enabling high torque capacity with low activation energy. However, such conventional devices enable a rotational engagement in a single direction only. Thus, in the event a bi-directional rotational engagement is needed, two clutches must be used. One to engage in a first direction, and the other to engage in the opposite direction. Or, in the event both clutches engage in the same direction, strategic positioning of the dual clutches relative to each other must occur to obtain the desired result of bi-directional engagement. In either case, the need for dual clutches (solenoids) can be costly and can complicate mechanical design factors for the application or device at issue.
Accordingly, an object of the present invention is to provide a bi-directional enabling solenoid actuated (spring clutch) device.